The present invention relates to a method of transporting piece goods and for organized changing their positions, especially for products of food industry. More particularly, it relates to such a method in accordance with which the goods are transported from a supply conveyor to a transporting device, then on the transporting device the goods are arranged in a predetermined position relative to one another, and then the goods are supplied by a subsequent discharge conveyor to their further treatment, for example, to a packaging machine.
The invention also relates to an arrangement for transporting piece goods and for organized change of their position, which includes a supply conveyor, a transporting device for transporting the piece goods with simultaneous organized changing of their position, and a discharge conveyor.
The processing of pieces which arrive in an irregular sequence, for example pastry pieces on automatic processing machines, such as packaging machines, which require constant arrival of the pieces or grouping of the pieces in time, for example, hose bag machines, wrapping up machines, etc. frequently a manual regrouping or collection is required, for example accumulation and subsequent separation of the individual pieces so as to provide for possibility to charge for example each chain compartment of a subsequent packaging machine.
This problem is especially complicated when the pieces arrive in several tracks and in each of these tracks in an irregular or in other words accidental and unexpected sequence, and on the other hand, must be supplied to a further processing machine for example in a plurality of rows arranged in a longitudinal direction and in a transverse direction with predetermined distances, and the accumulation of the pieces for subsequent separation in rows is not possible since the properties of the pieces (shape, sensitivity, adhesion, etc.) do not allow the accumulation (jamming).
A usual method of converting the pieces which are supplied irregularly in several tracks, into transverse rows is to orient or to accumulate the pieces on a beam or a barrier and cyclically discharge them into the rows. This is possible only for pieces with solid consistency and predetermined geometry.
For the case when the pieces are supplied strictly periodically or in other words with constant distances in the running direction, arrangements can be used which are disclosed in the German documents DE-OS 2,711,039 and DE-OS 3,147,590. In these arrangements a displaceable gap between two conveyors is moved periodically by means of curves, pulling means or fluid cylinder-piston units, and in particular in a co-running fashion exactly between two groups of pieces which must be separated from one another, so that by time- or workpiece-controlled variation of the transporting speeds, the group formation can be completely achieved.
However, the above described arrangements are incapable of forming groups from pieces which are supplied with irregular distances and in particular, in accidental unexpected fashion.
The possibility of compensating for accidental variations in the product supply is provided in the arrangement disclosed in the German document DE-OS 2,333,734. In this document the requirement is properly mentioned to influence the product supply by switching on or switching off of the prearranged machine when needed. With this arrangement, for each piece which is controlled at the outlet, a new piece must be supplied or fed at the inlet, so that it is in the position to compensate a time offset of the supplied piece.
All arrangements described in the above mentioned patents utilize a movable transition between two conveyors as a transition point, and also variable transporting speeds. They have only a short-time distributing function which is suitable for regrouping of regularly supplied or correctly withdrawn pieces. However, they do not have a simultaneous buffering function which is required for converting an accidental order of the pieces into a regular order of the pieces without inducing friction into the bottom of the transported goods.